Individually illuminated instrument casing



'July 21, 1942. M. KLEIN ETAL INDIVIDUALLY ILLUMINATED `INSTRUMENT CASING Filed Nov. 29, 1938 2 Sheets-Sheet 1 July 21, 1942. M, KLEIN ETAL 2,290,284

INDIVIDULLY ILLUMINATED INSTRUMENT CASING Filed Nov. 29, 1938 2 sheets-sheet 2 www Patented July 21, 1942 INDVDUALLY ILLUMINATED INSTRUMENT CASING Maximilian Mein, Sellcrsville,. and William E'. Pfeffer, South Perkasie, Pa., assignors to'United States Gauge Company, Sellersville, Pa., a co1'- poration of Pennsylvania.A

Application November 29, 1938, `Serial No. 243,046

(Cl. Mii-2.1)

9 Claims.

The present invention relates to novelcasing structures for individuallyr illuminated indicating instruments.

Indicating` instruments, usually, are mounted on an instrument board in position to be viewed by an operator seated or' otherwise stationed in front ofthe instrument board; Itis often difcult froml the operators position tof read such instruments, due to improper lighting of the dial of the instrument. Furthermore, when such instruments are mounted, particularly in the dashboards of automobiles, aeroplanes and the like, where the instrument must be read at night, it has been impossible to adequately illuminate the dial and pointers soV that a quick glance will enablea readixg of the instrument and eliminate undesired glare.

Under present illumination practices', when the dials and pointers are"l suiciently illuminated the light therefrom casts undesirable shadcwsin the vehicle or glares in the eyes ofV the operator so that the view from his seat, through the windshield, isseriously impaired.

It is, accordingly, the primary object ofv the present invention to provide a novel casing structure for usein a system of individual instrument illumination that permits the'readyr insertion of alam-p from theY front of the instrument and the making of the electrical contacts in the act of inserting theA lamp, all electrical conduits being concealed and included in the casing.

A further object of the present invention resides in providing the casing forv an illuminated indiciav bearing element with means for housing a light bulb and electrical connections whereby the; indicia bearing element may be illuminated byV directing rays of light into the interior o1 the element, andI across the face of the element, without"` causingglare.

A- further object ofthe present invention consistsv in adapting a casing for the mounting of a lens and prism designed to the light rays from the lamp and for supplying the electrical current to` the lamp to the casing Vfrom the rear of the instrument so that when the lamp is secured in the casing from the frcnt'all needed connections are thus made.

Another objectv of theepresent invention resides in adapting an instrument casing for the receptionv ofv a removable lamp designed forY edge illumination and'indirect' lighting of the indicia bearing elements.

Astill further object of the present invention resides in. providing a sealed casing adapted to receive a removable lamp, andA including wiring,

sockets and contactsL all built into the casing so that energy fcrthe lampis supplied through the back of the casing and the lamp maybe applied from the front whereit is readily accessible.

A further object ofthepresent invention resides in housing the electrical conduits, contacts, etc., of an individually illuminated instrumentin the instrument casing toprotect the same fromA injury, and to facilitate replacement of the` lamp and' permit its application from the-front of the instrument.

Otherobjectswill appear from this description and the appended claims whenV read in connection with theattached drawings, wherein:

Figure 1- is a plan view ofa preferred form ofy an indicating instrument embodying the present invention;

Figure 2 is a sectional view taken' on line 2-2 of Figure 1- and looking' in the direction oi"l the arrows;

Figure 3/ is a fragmental sectional View taken on line 3-3 of Figure l;

Figure 4- isa fragmental sectional view taken on line 4 4 of Figure 1;

Figure 5 is a detailed view'in' partial section illustrating the manner of fasteningl the reilector to the glare shield;

Figure' 6` is a plan view of a further modiiication of thepresent invention;

Figure '7 is a sectional view taken on line H El of Figure 6; and

Figures 8 and 9 are partial sectional views taken on lines |2-l2 and |3-l3 of Figure 6.

With continued reference to the drawings wherein like reference numerals areV employed to designate the same parts throughoutV the several gures ofv the drawings, numeral 8 indicates generally; thecasing of an indicating instrument of any desiredcharacter, such as a suction responsive gauge, a pressure gauge; a speedometer, a clockor the like.

Casing 8. comprises a cup-shaped body 9; preferably of Bakelite or the like; having the usual annular cover glass mounting recesses In, and recess ii for reception of the pointer actuation mechanism (not shown). An aperture I2 in body 9, permits connection of said mechanism to its actuating medium', while apertures I3 receive screws (not shown) for securing the `mechanism in casing 3. Casing 8 is provided with outwardly protruding ears I4 having apertures l5 therein, to receive elements I6 for mounting the instrument on a supporting structure. Elements i6 comprise internally threaded sleeves having one end il riveted over the shoulder I8 provided by the enlarged end of apertures |5, and a split, automatically locking, hexagonal head |9 overlapping the under face of ears |4.

To adapt casing 8 for illumination purposes, body 9 is provided with a rearwardly extending boss 2| which is formed to provide a suitable electrical socket 22. Socket 22 comprises an outer sleeve-like terminal member 23, embedded in boss 2|, and a centrally positioned rod-like terminal member 24, embedded in boss in spaced relation to member 23. Member 23 has an annular groove 25 therein designed to cooperate with a portion of an electrical plug (not shown) which is connected to a suitable source of electrical power. Member 24 is provided with a bore 26 extending part way therethrough designed to receive a mating portion of the above-mentioned electrical plug.

A secondary contact plate 21 on the interior wall 28 of body 9 is connected to member 24 by means of a screw 28 which passes through a suitable aperture in body 9 and is threaded into member 24. A similar secondary contact plate 29 is connected to member 23 by means of a screw 28 in exactly the same manner.

Body 9 is also provided at one side with an elongated boss 3| Boss 3| is hollowed out to house the lamp and provide a bulb-socket 32 therefor.

Socket 32 is connected to socket 22 by an electrical conduit 33. Conduit 33 may take any desired form but preferably consists of an electric wire 34 having suitable insulation 35 therearound encased in a flexible metal sheath 35.

One end of wire 34 is connected to contact plate 21 and the corresponding end of sheathing 35 is connected to contact plate 29.

The sheathing 36 at the end of conduit 33 remote from socket 22 is cut back to provide a portion 21 which is not severed from the remainder of the sheathing. Theexposed insulation is removed from wire 34 an appreciable distance from the joint between the portion 31 and the remainder of sheathing 36. The bared end 3B of wire 34 is then passed through a suitable aperture 39 in the casing into bore 4| in boss 3|. Bore 4| extends the whole length of boss 3| and at its upper end is provided with an enlargement 42, the purpose of which will presently appear.

End 38 of wire 34 is soldered in loop 43 of conduit 44 which is supported by a concentric, insulating, ring-shaped, sleeve 45 fitted snugly in bore 4|. Suitable arms 46 passing through apertures 41 of sleeve 45 serve to connect conduit 44 to sleeve 45. The upper end of conduit 44 is provided with an annular socket contact member 49 which engages end 48 of sleeve 45. Sleeve 45, therefore, serves to back-up contact 49 and prevents downward bending of contact 49 in use. Contact 49 has a, central aperture 5| therein. The purpose of contact 49 will be hereinafter pointed out in detail.

The portion 31 of sheathing 3G is soldered to one end of a conduit member 53 which passes through a suitable passage 54 in body A9 into bore 4| and up the wall of bore 4| in a groove 55 provided for that purpose. A similar groove 56 receives the portion of conduit 44 which passes up the wall of bore 4|. Conduit 53 is bent over into enlargement 42 and clamped in place by means of an internally threaded metal socket contact ring 51, the purpose of which will presently appear.

Apertures 39 and 54 are preferably formed by boring through boss 3| and body 9 from the outside of boss 3|. The outer ends of the resulting openings are then sealed with suitable cement as at 59. The space around conduits 38 and 53 in apertures 39 and 54 is similarly sealed to render the casing pressure-tight and to secure the electrical conduits in place.

A suitable miniature light bulb 59, preferably of three volt capacity, is inserted through socket 32 of boss 3| and makes contact with contact ring 49 at 6|, and with contact ring 51 through metal protecting cap 62 at 63. Cap 62 is screwed into contact ring 51 with sufcient pressure to retain bulb 59 in place and assure good electrical connections with the socket contacts.

The Contact 49 is the live contact and contact 51 is the return or ground contact. Consequently, the electrical plug from the power source is so designed that the current passes to member 24 of socket 22, contact plate 21, through wire 34, conduit 44, contact 49, contact 6| of bulb 59 and returns from contact 63 of bulb 59 through cap 62, to contact 51, conduit 53, sheathing 3S, contact plate 29, member 25 to the return line of the power source.

Body 9, adjacent the lower end of sleeve 45, is provided with a wedge-shaped aperture 65 (Figures 1 and 5), the upper edge of which coincides with the bottom of sleeve 45. The smaller end of aperture 65 intersects bore 4| while the larger end intersects recess of body 9. A wedge-shaped prism G9 corresponding in shape to aperture 66 is disposed in the aperture with its smaller end protruding into and extending slightly more than half way across bore 4| Prism S8 provides an external totally reecting surface 69 and is held in place by a suitable cement, such as Glyptol lacquer. Reflecting surface 69 is of arcuate shape in plan and slopes inwardl`y from top to bottom at an angle of 45 so that the light rays from bulb 59 will undergo total reection and pass through prism 58 at right angles to the axis of bore 4|.

A bulls eye lens 19 is preferably secured by Glyptol lacquer in the lower end of sleeve 45, so as to rest upon the upper surface of prism 68. Lens 19 is so designed that the normally divergent light rays from bulb 59 will be refracted so as to leave the exit face of lens 10 in a direction paralleling the axis of bore 4|.

Body 9 is also provided with a shallow annular shoulder 1| which is designed to receive a corrugated metal reflector 12. Reflector 12 is preferably flexible, yet rigid enough to retain its position when placed on shoulder 1|. The ends 13 of .reflector 12 are fastened at points in alignment with the intersection of the side faces and the exit face of prism 68 by hooking apertures 14 of ring 13 behind corners 14 of a glare shield 15 (Figures 1, 2 and 5). Glare shield 15 is in turn cemented at 19 to the exit face of prism 68 in alignment with the top of a dial 11 carried by indicating mechanism M (Figure 3). Shield 15 prevents direct rays of light from passing from the exit face of prism 59 past the edge of dial 11 to cause a glare.

The illumination of the instrument of Figures l to 5 is accomplished in the following manner, Socket 22 is connected to a suitable source of electrical energy and through conduit 33 lights bulb 59 in boss 3|. The normally divergent rays of light from bulb 59 pass into the bulls eye lens 10 entering the lens through the convex face and emerging through the flat exit face as parallel rays in a manner well known in the art. The rays passing through the portion of lens 'I0 overlying the protruding end of prism 68 enter prism 68, A major portion of these last mentioned rays strike arcuate, total reflecting surface 65 and are bent at right angles and pass radially through prism 58. These radially travelling rays of light spread out in a fan shaped manner to illuminate the indicia bearing element and indicating elements of mechanism M.

For a more detailed disclosure of the system of lighting and bulb 59, reference may be had to copending applications of Maxmilian Klein and William E. Pfeffer entitled Illuminating indicating instruments, Serial No. 243,045, filed on even date herewith, and Miniature bulb and socket construction Serial Nos. 243,047 and 243,- 048 iiled on even date herewith which latter two applications have matured into Patent No. 2,- 210,764, dated August 6, 1940, and Patent No. 2,190,875, dated February 20, 1940.

A further modication of the invention is disclosed in Figures 6 to 8. In this form of the invention, a casing 9b substantially like that of Figures 1 to 4 is used. As a consequence, the

same reference numeralsl will be used for the identical parts and the detailed description thereof will be omitted.

In this form of the invention, casing 8b, comprises a body 9b designed to receive two indicating mechanisms, for example, an air gauge and a fuel gauge both of which cooperate with a single dial member lili having suitable scales (not shown) thereon. These gauges are mounted in recess I and the bottom wall 28 is provided with two apertures I2 and two sets of apertures I3. Conduit 33 is connected to socket 22 as heretofore described, and the opposite end thereof is passed through an enlarged opening interconnecting space i! and bore alb, of boss 35h.

End 3S of wire iid is soldered to a spring metal contact member H2 which is disposed in groove 55 and end 3'! of sheathing 35 is soldered to the bared end of insulated conduit ||3 which is disposed in groove 55. The opposite end of conduit ||3 is clamped between metal bulb adaptor Ila and an insulating sleeve or ring I I5 threaded into adaptor Hd. Sleeve I|5 encircles metal contact bushing l I5 and clamps flange Ill of bushing I I6 against insulating washer Ii which is in turn clamped against shoulder H9 of adaptor H4.

The `protruding end I2! of bushing IIS extends into bore Mb and is threaded into complementary metal contact bushing |22 and bears upon the edge of the convex surface of bulls eve lens lll to clamp lens 'Ill against shoulder |23 of bushing |22. Bushing |22 extends to a point adjacent the bottom of bore 4|?) and is internally threaded at |24. A screw |25 having suitable wrench receiving apertures |26 therein is threadedly engaged with threads |24 and secures adaptor IM, washer I IB, contact bushing H5, insulating ring H5, contact bushing I 22 and lens 'l5 in proper position in bore 1b. Suitable sealing gaskets |27 are preferably disposed between the end faces of boss Sib and adaptor ring I Il and screw |25 to assure a pressure-tight point at these points. To prevent a short circuit between contact I I2 and conduit I I3 at their point of jointure with end 33 of wire 3:7 and portion 3l of sheathing 3E, an insulating washer |28 having a radially extending tab |29 is disposed against the lower end face of bushing 22 with tab |25 extending into aperture III and overlying the end of conduit 33.

In order that light from bulb 59 may reach prism |53, the wall of bushing |22 adjacent the prism is provided with a peripheral slot I3 The protruding end of prism 68 extends through slot ISI with its reilecting surface located below the flat exit face of lens 1|).

Bulb 59 is lighted over the following circuit: from live terminal 24 of socket 22 through plate 2:7, wire 34, contact l2, contact bushing |22, bulb contact 5|, the bulb filament, bulb contact 63, adaptor I4, conduit I3, sheathing 35 to ground or return terminal 23 of socket 22.

The invention may be embodied in other specinc forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1` A casing for an indicating instrument comprising a cup-shaped body portion having a rear Wall and an open face, an electrical socket imbedded in and projecting from the rear Wall, electrical conducting means passing from the i-mbedded portion of said socket through said rear wall to the interior thereof and providing electrical contacts within the interior of the cupshaped body, means formed in the interior of the peripheral wall of said cup-shaped body adjacent said open face for receiving a cover glass and a cover glass securing ring, a peripheral shoulder in said last mentioned wallvadjacent said means for receiving a light reflecting element, a split, annular reflecting element on said shoulder having its two ends in spaced relation, an external protuberance `formed on said body at a point adiacent said spaced ends of said reflector and having a bore therein, a passageway through said peripheral wall interconnecting the interior of said cup-shaped body and said bore, said passageway having one end located in the space between the ends of said reflector and providing passage for light rays from said bore to the interior of said cup-shaped body, a lamp socket in said protuberance, electrical conduit means within the interior of said body interconnecting said contacts in the interior of said cupshaped body and said lamp socket and passing through the common wall of said body and protuberance, and means preventing the passage of through the bore of said protuberance between the interior of said body and the atmosphere.

2. The combination dened in claim l. wherein said bore is provided with a pair oi longitudinally extending grooves for receiving said electrical conduits; an insulating sleeve for retaining the conduits in said grooves, and a condensing lens for paralleling light rays before they enter said passageway.

3. An instrument casing designed for individual illumination comprising an, integral cupshaped body and hollow boss having a common wall, said boss having a front end adjacent the open or front end of the cup-shaped body, and the hollow therein being provided by a longitudinal bore open at the front end; a plurality of spaced contacts for receiving a lamp inserted from the front of said casing with its head in said bore, whereby light from said lamp will be directed into the bore; a condensing lens below said contacts and occupying substantially the cross-sectional area of said bore; transparent means below said lens providing a light passageway between said bore and the interior of said cup-shaped body and for reecting light from said lens into said interior; an electrical connection on the rear wall of said body; and electrical conducting means between said contacts and said connection, said conducting means lying adjacent the walls of said bore and passing through said common wall below said transparent means, thence through the interior of said body to the rear wall and said connection.

4. The combination defined in claim 3 wherein said transparent means and said conducting means are sealed where they pass through said common wall whereby the cup-shaped body interior is sealed against leaks through said bore.

5. The combination dened in claim 3 wherein a single passageway for said reflecting means and said conducting means is provided in said common wall, and said bore is provided with means for sealing said bore and communicating cup-shaped body interior against air leakage.

6. An instrument casing for use in individually illuminated indicating or like instrument oomprising a cup-shaped non-conducting body having an open face and a rear wall, an electrical socket embedded in the rear wall and projecting from the back thereof, electrical contacts on the inner surface of said rear wall, extending through a portion of said wall and connected to the imbedded part of said socket, a boss formed on the peripheral wall of said body and having a bore therein, lamp socket contacts in said bore, a pair of relatively small passages through the peripheral wall of said body interconnecting the interior of the body and said bore, electrical conduits extending through said passages and interconnecting said contacts on said rear wall and said lamp socket contacts, means sealing said passages against leakage of air therethrough, and means for transmitting light from said bore through said peripheral wall and into the interior f said body.

'7. An instrument casing for use in individually illuminated indicating or like instruments, comprising a non-conducting cup-shaped body having an open face and a rear wall, an electrical socket embedded in the rear wall and projecting from the back thereof for connection to a source of electrical energy, means connected to and passing from the imbedded portion of said socket to the interior of the rear wall to provide contact-s on the inner surface of said rear wall, a boss formed on the peripheral wall of said body and having a bore separated from the interior of the casing by said wall, lamp socket contacts in said bore, at least one passage through the peripheral wall of said body interconnecting the interior of the body and said bore, an electrical conduit extending through said passage and interconnecting said contacts on said rear wall and said lamp socket contacts, means for receiving a lamp in said bore so as to engage said contacts, means for transmitting light from said lamp through said peripheral wall and into the interior of said body, and means preventing the leakage of air to or from the interior of said casing through said .bore to the atmosphere.

8. An individually illuminated casing designed to accommodate an indicating instrument for use with a dial member, comprising a cup-shaped body having a rear wall and providing a space for an indicating instrument, a socket member accessible from the exterior of said rear wall for connection to a source of electrical energy, electrical conductors connected to said socket and providing contacts on the interior of said rear wall, a boss on the peripheral wall of said body providing a lamp housing and socket, means forming a light passageway through said peripheral wall from said lamp housing to said space, and an electrical conduit interconnecting said contacts and said lamp socket passing through said last-mentioned passage, wherein said lamp housing and socket comprise a bore in said boss, a sleeve having internal threads in its opposite ends and a notch in its peripheral wall, a pair of grooves in the wall of said bore forl receiving electrical conduits, an electrical conduit in each of said grooves one of which makes electrical contact with said sleeve, a second sleeve having an externally threaded portion for engagement with one end of said rst mentioned sleeve and forming an electrical contact for a lamp, an insulating ring snugly tting around said second sleeve and having an external threaded portion, a flange on said second sleeve engaging an end face of said ring, a metal adapter s-crewthreadedly engaged with said ring to secure said other conduit therebetween and having a threaded aperture of smaller diameter at the end opposite that threadedly engaged with said ring, an insulating washer between the anged end of said second sleeve and the portion of said adapter surrounding said threaded aperture of smaller size, a lamp freely received in said threaded aperture of smaller size having an electrical contact engaging said second sleeve, a metallic protesting cap threaded into said smaller sized aperture and engaging the end of said lamp to clamp the lamp in the socket and complete the circuit to said adapter and other conduit and a headed screw-threaded fastener engaging the internal thread of the oiher end of said iirst--mentioned sleeve to secure the lamp housing and socket elements in place in said bore.

9. A casing for an instrument designed for individual illumination, comprising a cup-like body having a hollow boss projecting laterally of said body at the edge of the open end thereof and adapted to receive an electric bulb at one end portion; means in the wall of said body between the inside of said cup and said hollow boss for reflecting light rays emitted by the lamp from said hollow boss to the inside of said body; electric lamp contacts in the hollow of said boss near the lamp receiving end portion; light condensing means between said reecting means and said lamp contacts; an electric socket in the back wall of the casing, and conductors on the inside of said casing and connected to said socket and contacts, said conductors passing from the inside of said body to the inside of said boss at a point below said reiiecting means and thence along the inner wall of said hollow boss, whereby they do not interfere with the passage of light through said means.

MAXIMLIAN KLEIN. WILLIAM E. PFEETER. 

